Angiotensin II effects on the cytosolic free Ca2+ concentration in N1E-115 neuroblastoma cells: kinetic properties of the Ca2+ transient measured in single fura-2-loaded cells.
The effect of angiotensin II on the cytosolic free Ca2+ concentration was measured in single mouse neuroblastoma N1E-115 cells loaded with fura-2. Angiotensin II induced a transient concentration-dependent increase in Ca2+ and also increased the production of inositol polyphosphates. The Ca2+ increase did not require extracellular Ca2+ and was unaffected by pretreatment with pertussis toxin. These data suggest that angiotensin II increased Ca2+ by an inositol trisphosphate-mediated release of intracellular Ca2+ following activation of phospholipase C via a pertussis toxin-insensitive guanine nucleotide binding protein. Similar results were obtained with bradykinin. The angiotensin II- or bradykinin-induced increase in Ca2+ occurred after a concentration-dependent latent period. Low concentrations of agonist elicited a small increase in Ca2+ following a variable lag that sometimes exceeded 1 min, whereas at maximally effective angiotensin II concentrations a larger, more rapid increase in Ca2+ occurred without a measurable delay. In some cells, oscillatory increases in Ca2+ were induced by angiotensin II and bradykinin. Possible mechanisms to explain the concentration dependency of the latent period and the oscillatory nature of the increases of Ca2+ are discussed. These results indicate that the mouse neuroblastoma N1E-115 cell represents a useful model for studying the signal response transduction mechanisms regulating the effects of angiotensin II in neuronal cells.
Monck
J R
JR
Department of Biochemistry and Biophysics, School of Medicine, University of Pennsylvania, Philadelphia 19104.
Williamson
R E
RE
Rogulja
I
I
Fluharty
S J
SJ
Williamson
J R
JR
D000804:Angiotensin II / Q000494:pharmacology*; D000818:Animals; D001572:Benzofurans; D001920:Bradykinin / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism*; D002454:Cell Differentiation; D002455:Cell Division; D002460:Cell Line; D003600:Cytosol / Q000187:drug effects / Q000378:metabolism; D005456:Fluorescent Dyes; D016257:Fura-2; D007295:Inositol Phosphates / Q000378:metabolism; D007700:Kinetics; D051379:Mice; D009243:NAD / Q000378:metabolism; D009447:Neuroblastoma; D037342:Pertussis Toxin; D014407:Tumor Cells, Cultured / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D010566:Virulence Factors, Bordetella / Q000494:pharmacology
D001572:Benzofurans; D005456:Fluorescent Dyes; D007295:Inositol Phosphates; D010566:Virulence Factors, Bordetella; D009243:NAD; D000804:Angiotensin II; D037342:Pertussis Toxin; D001920:Bradykinin; D002118:Calcium; D016257:Fura-2